The present invention relates generally to cryogenic storage vessels and more particularly to vehicle-mounted tanks capable of being manufactured in a variety of sizes.
The typical cryogenic storage vessel consists of a cylindrically-shaped inner storage vessel for holding liquid natural gas ("LNG") or other cryogen under pressure ranging from about 50 psig to about 300 psig. A relatively thin outer shell of the same general shape and slightly larger dimension surrounds the inner storage vessel, forming an insulation chamber therebetween. The outer shell has a port to allow evacuation of air from the insulation chamber.
Prior to evacuation, thermal insulating material is disposed in the insulation chamber to prevent radiant and conductive heat transfer between the external environment and the internal storage vessel. Cryogenic storage vessels of this type are generally described in U.S. Pat. No. 4,548,335 to Remes.
One particular use for cryogenic vessels is to store LNG, which may be used to fuel specially equipped vehicles. The LNG is stored in on-board vessels analogous to the gas tank on conventional automobiles. On these vehicles, space is limited, so the size and shape of the LNG storage vessel must be optimized. A vessel having a horizontal dimension greater than its vertical dimension allows greater storage capacity while maintaining ground clearance. However, different types of vehicles have different space limitations. Ellipsoidal storage vessels can be specially fabricated, but providing matched pairs of pressure heads is difficult and time consuming. A unique forming die must be made for each desired size of storage vessel. A cryogenic storage vessel that may be easily and cheaply fabricated for assembly in a wide range of sizes to fit various vehicle designs is desirable.
Accordingly, it is a general object of the invention to provide a vehicle-mounted cryogenic storage vessel.
It is a further object of the invention to provide such a vessel that may be assembled in a variety of sizes.
It is another object of the invention to provide such a vessel that is of durable, low-cost construction.
These and other objects of the invention will become apparent when the following detailed description of the invention is read in conjunction with the accompanying drawings.